Looks like Julia added some color to her hair for a pre-Halloween party, maybe ... and forgot to wash it out???

Access Hollywood site pointed out the red streaks in Robert's hair -- the actress was in San Fran to honor and raise funds to the late Paul Newman's charity The Painted Turtle, a camp for children with life threatening diseases.

But Julia explained that it was her daughter Hazel who told her, "Mommy, I wish you had pink hair." So the superstar mom obliged and put in a few streaks :) -- CUTE!